Objects & Arrays

cycle

Produces one of its arguments each time this tag is encountered. The first argument is produced on the first encounter, the second argument on the second encounter, and so forth. Once all arguments are exhausted, the tag cycles to the first argument and produces it again.

In the following example, a player is either in the odd or even side:

INSERT INTO players (side) VALUES
  {% for player in game.players %}
    ('{% cycle "odd" "even" %}') {% if forloop.Last %};{% else %},{% endif %}
  {% endfor %}

This outputs:

INSERT INTO players (side) VALUES
  ('odd'),
  ('even'),
  ('odd'),
  ('even');

You can use the {% resetcycle %} tag to make a {% cycle %} tag restart from its first value when it's next encountered.

firstof

Outputs the first value that is not "false" (i.e. exists, is not empty, is not a false boolean value, and is not a zero numeric value). Outputs nothing if all the passed variables are "false".

Given the following data:

{
  "choice1": "",
  "choice2": "none",
  "choice3": "",
}

And given this template SQL:

INSERT INTO settings (notifications_mobile) VALUES
  ('{% firstof choice1 choice2 choice3 %}');

The output is:

INSERT INTO settings (notifications_mobile) VALUES
  ('none');

The template equivalent only with conditions tags would be:

INSERT INTO settings (notifications_mobile) VALUES
  {% if choice1 %}
    ('{{ choice1 }}');
  {% elif choice2 %}
    ('{{ choice2 }}');
  {% elif choice3 %}
    ('{{ choice3 }}');
  {% endif %}

You can also use a literal string as a fallback value in case all passed variables are "false":

INSERT INTO settings (notifications_mobile) VALUES
  ('{% firstof choice1 choice2 choice3 "default" %}');

for

Loops over each item in an slice, array or map, making the item available in a scoped variable.

Accessing the value for each iteration inside a slice, array, map:

INSERT INTO players (username) VALUES
{% for player in game.players %}
  ('{{ player.username }}'){% if forloop.Last %};{% else %},{% endif %}
{% endfor %}

Accessing the key and the value for each iteration inside a map:

INSERT INTO kv_store (key, value) VALUES
{% for k, v in context %}
  ('{{ k }}', '{{ v }}'){% if forloop.Last %};{% else %},{% endif %}
{% endfor %}

reversed

You can loop over a list in reverse by adding reversed to a {% for %} tag:

INSERT INTO players (username) VALUES
{% for player in game.players reversed %}
  ('{{ player.username }}'){% if forloop.Last %};{% else %},{% endif %}
{% endfor %}

forloop. variables

The for loop sets a number of variables available within the loop:

• forloop.Counter is the current iteration of the loop, 1-indexed.
• forloop.Counter0 is current iteration of the loop, 0-indexed.
• forloop.Revcounter is the number of iterations from the end of the loop, 1-indexed.
• forloop.Revcounter0 is the number of iterations from the end of the loop, 0-indexed.
• forloop.First is True if this is the first time through the loop.
• forloop.Last is True if this is the last time through the loop.
• forloop.Parentloop is for nested loops. This is the loop surrounding the current one. It also gives access to the forloop. variables of the parent one.